According to research published in the April issue of Hypertension: Journal of the American Heart Association, blood pressure may be affected both by environmental factors such as ambient personal temperature and the number of daylight hours.
The study found that for every increase of 1C (1.8F) in “personal-level environmental temperature” (temperature measured close to the patient) was associated with a 0.14mmHg drop in average daytime systolic blood pressure.
It also found that for every hour of extra daylight experienced, the average nighttime systolic blood pressure rose by 0.63mmHg
Both relationships were statistically significant only for those patients who were on antihypertensive drugs.
The researchers noted that normally the rise in blood pressure due to the increase in daylight hours from winter to summer is balanced against the reduction in blood pressure due to increasing air temperatures.
However, the unseasonably cold weather so far this Spring may be upsetting this balance, putting Hypertension suffers at greater risk of higher blood pressure.
The researchers wrote, “Monitoring the antihypertensive treatment in elderly patients under conditions of unstable and often extreme temperature exposures is, thus, further supported by our data, especially in the light of the debate on the possible effects on health of current world climate change.”
The study involved 1,897 patients who were referred to Italian hypertension clinics and who underwent ambulatory blood pressure monitoring accompanied by a measurement of personal-level environmental temperature.
The average age of patients was 63 and two thirds were receiving antihypertensive drugs.